1. Field of the Invention
The invention relates to a wide converter lens having a compact structure, and embodying a wide viewing angle by being attached to a main lens.
2. Description of the Related Art
Recently, use of optical imaging devices, such as digital still cameras or digital camcorders, including a solid-state imaging device such as a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS), each of which converts an optical image into an electrical signal, is rapidly increasing.
Thus, demands for compact and lightweight optical imaging devices, in addition to optical imaging devices having high performance such as a high resolution and a wide viewing angle, are also increasing.
Since a conventional imaging lens has a limited viewing angle, wide converter lenses are used to widen the viewing angle. That is, a given viewing angle is changed by attaching a wide converter lens to a main lens. Wide converter lenses, however, have a complicated structure, and thus when used to widen the given viewing angle, distortions or aberrations may be increased.
Although various wide converter lenses have been developed, it is still difficult to obtain a wide viewing angle using a small number of lenses. For example, when the viewing angle is widened, aberrations are increased. Although such an increase in aberration of an optical imaging device can be corrected by using more lenses, the manufacturing costs, the size and the weight thereof are increased.